This study is a three segment study, Phase 1/2 study of the use of recombinant factor IX in severe factor IX deficient patients that have previously been treated with factor therapies made from pooled human plasma. It involves a double-blinded randomized crossover evaluation of the pharmacokinetics including a recovery and half-life study of rhFIX and Mononine, an open-label, on demand treatment of bleeding episodes using rhFIX; and intra- and postoperative treatment using rhFIX.